🧪 test: Add testing for SettingsViewModel toggleDarkMode function

feature-settings/build.gradle.kts

@@ -43,4 +43,6 @@ dependencies {
 
     implementation(libs.hilt.android)
     ksp(libs.hilt.compiler)
+    testImplementation(libs.junit)
+    testImplementation(libs.kotlinx.coroutines.test)
 }

feature-settings/src/test/java/com/sayanthrock/rockreleasehub/feature/settings/SettingsViewModelTest.kt

@@ -0,0 +1,40 @@
+package com.sayanthrock.rockreleasehub.feature.settings
+
+import org.junit.Assert.assertEquals
+import org.junit.Before
+import org.junit.Test
+
+class SettingsViewModelTest {
+
+    private lateinit var viewModel: SettingsViewModel
+
+    @Before
+    fun setup() {
+        viewModel = SettingsViewModel()
+    }
+
+    @Test
+    fun initialStateIsSuccessWithDarkModeTrue() {
+        val expectedState = SettingsState.Success(isDarkMode = true)
+        assertEquals(expectedState, viewModel.uiState.value)
+    }
+
+    @Test
+    fun toggleDarkMode_changesDarkModeToFalse() {
+        // Initial state is true
+        viewModel.toggleDarkMode()
+
+        val expectedState = SettingsState.Success(isDarkMode = false)
+        assertEquals(expectedState, viewModel.uiState.value)
+    }
+
+    @Test
+    fun toggleDarkMode_twice_changesDarkModeBackToTrue() {
+        // Initial state is true
+        viewModel.toggleDarkMode() // to false
+        viewModel.toggleDarkMode() // back to true
+
+        val expectedState = SettingsState.Success(isDarkMode = true)
+        assertEquals(expectedState, viewModel.uiState.value)
+    }
+}